The present invention relates to a remover solution for photoresist or, more particularly, to a remover solution for a photopolymerization-type photoresist containing an acrylic resin or a positive-working photoresist containing a phenolic resin.
Photopolymerization-type photoresist compositions containing an acrylic resin are widely used in the prior art in the manufacturing process of various kinds of electronic components such as printed circuit boards, substrates of semiconductor devices and the like with an object to form a protecting film on the substrate surface as an etching resist, soldering resist, plating resist and the like.
To outline the manufacturing process by using a photopolymerization-type photoresist composition containing an acrylic resin, the surface of a substrate is coated with the photopolymerization-type photoresist composition in the form of a solution followed by drying and then the coating film of the resist composition is exposed patternwise to actinic rays such as ultraviolet light through a negative photomask bearing a desired pattern followed by a development treatment to form a patterned resist layer. Thereafter, the substrate surface is subjected to a treatment of etching, soldering, plating and the like selectively with the patterned resist layer as the protecting film for the substrate surface. After completion of the treatment, the patterned photoresist layer is removed by using a solvent or a solvent mixture which is called a remover.
It is known that conventional removers for removing a patterned resist layer contain, as the principal ingredient thereof, one or more of chlorinated hydrocarbon solvents such as trichloroethylene, methylene chloride and the like. These conventional removers have several disadvantages and problems.
For example, a photoresist composition cured by exposure to actinic rays such as ultraviolet light cannot be dissolved by these removers containing the above mentioned chlorinated hydrocarbon solvents but the cured photoresist layer is merely swollen with the solvents so that the swollen photoresist layer falls off the substrate surface in pieces. Accordingly, drawbacks are sometimes unavoidable that removal of the photoresist layer is incomplete to leave residue of the photoresist layer on the substrate surface or the photoresist layer which has once fallen in pieces from the substrate surface may be re-deposited on the substrate surface resulting in the occurrence of unacceptable products.
Moreover, a remover solution once used in a removing process sometimes contain pieces of the swollen photoresist layer suspended therein so that a remover solution once used cannot be re-used as such without being freed from the suspended pieces of the swollen photoresist layer to cause an economical disadvantage.
It is therefore eagerly desired to develop an efficient remover solution which can completely dissolve a photocured resist layer on the substrate surface to solve the above mentioned problems in the prior art remover solutions but no successful proposals have yet been made to provide a remover solution as desired.